Choroidal neovascularization of the macula (CNVM) is the chief cause of blindness over age 50. Within recent months, there have been reports of the first statistically significant benefit for this disorder from both focal radiotherapy, using higher doses than previously employed, and photodynamic therapy. Investigations are still early but both methods are promising and could potentially be used in combination. During Phase I of this proposal, a prototype device and associated techniques were developed permitting focused radiotherapy with a conventional linear accelerator in a manner technically equivalent or superior to the proton beam methods employed to date, but at far lower potential cost and greater general availability. In Phase II, this device would be refined to facilitate its routine clinical use in the field and to enable its reproduction for institutions wishing to participate in clinical trials, and dosimetry studies would be completed. PROPOSED COMMERCIAL APPLICATION: If focal macular irradiation proves as safe and effective as current evidence suggests it will be, this device would be used in approximately 2000 radiotherapy facilities to treat over 100,000 cases per year in the U.S.A. alone.